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From: B.Hamilton@irl.cri.nz (Bruce Hamilton)
Newsgroups: sci.chem
Subject: Re: SEMTEX - what is it?
Date: Fri, 15 Dec 1995 19:41:52 GMT
Organization: Industrial Research Limited
yshan@bnr.ca (Yogi Shan) wrote:
>Jason Ritchie <jaritchie@mail.utexas.edu> wrote:
>:Willis Nelson (wnelson@cs.strath.ac.uk) writes:
>:>does anyone know what Semtex is? Is it a mixture,
>:>or is it mostly a single compound? Thanks to anyone...
>:I seem to remember it's something like 80% HMX,
>:20% RDX. Just numbers off the top of my head. :)
>Plasticized PETN was the answer someone posted
>previously to rec.pyrotechnics, listing the 1990's
>vintage book by VCH Publishers (entitled, "Explosives")
>as a reference.
According to an article in C&EN ( July 24 1995 p.19 ),
it's a mixture ( no ratios given ) of :-
RDX ( cyclotrimethylenetrinitramine)
PETN ( pentaerythritol tetranitrate )
Poly(butadiene-styrene)
Oil
Cited reference was:-
"Modern Methods and Applications in Analysis of Explosives"
Jehuda Yinon and Shmuel Zitrin
John Wiley and Sons (1993)
I'll check, and add to the FAQ
Bruce Hamilton
From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: sci.chem,alt.engr.explosives
Subject: Re: SEMTEX - what is it?
Date: 19 Dec 1995 01:06:58 GMT
Organization: Consulting Chemist
In article <4b4pf4$qnp@bcarh8ab.bnr.ca>, yshan@bnr.ca (Yogi Shan) says:
>I find it strange that PETN would be mixed with
>RDX. _Plastique_ is _plastique_. RDX (the
>explosive in C4), I understand is more expensive
>than PETN, and would require a separate
>production line.
You are right, Yogi. PETN and RDX are so similar in their explosive
properties that it would be foolish to mix the two and thereby
double the risk of some chemical incompatibility unique to one or
the other.
By coincidence, it happens that I have prepared and tested plastic
explosives that have about the same composition as the material that
is now called "Semtex." The compositions are very similar to
C-4 in look, feel and performance.
In the US, RDX has been viewed as a "military" explosive. PETN,
was considered more as a "commercial" explosive, partly
because of its private industrial manufacture and widespread
use in detonating cord. RDX, of course, works just as well in det
cord and is the basis for the military version. Industrial
use of RDX is mostly limited to surplus powder which is cast
into primers in admixture with TNT..
If you ask US military folks why they use RDX rather than PETN,
they will usually cite the somewhat lower density and greater
sensitivity of PETN. Besides, it's a habit and it costs the
taxpayer more :)
Jerry (Ico)
From: B.Hamilton@irl.cri.nz (Bruce Hamilton)
Newsgroups: sci.chem
Subject: Re: SEMTEX - what is it?
Date: Tue, 19 Dec 1995 17:12:33 GMT
Organization: Industrial Research Limited
yshan@bnr.ca (Yogi Shan) wrote:
>B.Hamilton@irl.cri.nz (Bruce Hamilton) wrote:
>:yshan@bnr.ca (Yogi Shan) wrote:
...
>VCH is a German publisher, and the Germans, to their
>misfortune, had quite a bit of experience with
>Semtex. It's a 4th edition of the book too, and
>it's listed in '95 "Books in Print", though a
>little expensive, which is why I don't have it.
[ I referenced it in the FAQ as ]
Explosives - 4th edition
R.Meyer
VCH (1993) ISBN 1-56081-266-4
I went to our public library, unfortunately they only had the 3rd edition,
and there was no mention of Semtex in the index or the body of the
text from what I could see. Unfortunately, the translation was pretty
horrific, and the reason I referenced it was that it does have
brief, easily-read mongraphs on a wide range of explosives.
>The _J. For. Sci._ should have something on this.
I will try to check before the next FAQ update, but the journal
back issues are no longer conveniently available.
Bruce Hamilton
From: B.Hamilton@irl.cri.nz (Bruce Hamilton)
Newsgroups: sci.chem,alt.engr.explosives
Subject: Re: SEMTEX - what is it?
Date: Wed, 20 Dec 1995 04:45:43 GMT
Organization: Industrial Research Limited
In article <4b537i$k9@geraldo.cc.utexas.edu>
glhurst@onr.com (Gerald L. Hurst) writes:
>In article <...>, yshan@bnr.ca (Yogi Shan) says:
[ my earlier cite to C&EN, noting that Semtex had
both RDX and PETN deleted ]
>>I find it strange that PETN would be mixed with
>>RDX.
...
>You are right, Yogi. PETN and RDX are so similar in their explosive
>properties that it would be foolish to mix the two and thereby
>double the risk of some chemical incompatibility unique to one or
>the other.
>
>By coincidence, it happens that I have prepared and tested plastic
>explosives that have about the same composition as the material that
>is now called "Semtex." The compositions are very similar to
>C-4 in look, feel and performance.
Well, as promised, I looked it up. Experience tends to make me
very suspicious of Gerald's assertions :-)....
From:- "Analysis of Semtex Explosives" J.R.Hobbs.
Chapter 39. p.409-428 in " Advances in Analysis and
Detection of Explosives" edited by Jehuda Yinon
Kluwer Academic Publishers ISBN 0-7923-2138-3 (1993)
Table 1. Summary of Semtex Analysis
Name Semtex H Semtex A
% PETN 49.8 94.3
% RDX 50.2 5.7
Dye Sudan I Sudan IV
Antioxidant N-phenyl-2- N--phenyl-2-
naphthalamine naphthalamine
Plasticizer n-octyl phthalate n-octyl phthalate
butyl citrate butyl citrate
Binder styrene-butadiene styrene-butadiene
rubber rubber
Table 2. Gravimentric Analysis
Sample size 1.0194 1.1061
Weight oil 0.0811 0.0994
% oil by weight 7.9 9.0
weight rubber 0.0920 0.1036
% rubber by weight 9.0 9.4
weight explosives 0.7029 0.7029
[ rest of table omitted ]
Note that other chapters highlight the fact that Semtex H was the
explosive used in mainland UK. There is an excellent, droll
chapter " The Semtex H Story" by A.W.Feraday,OBE - head of
Forensic Investigations, Forensic explosives Laboratory. He
describes all 58 incidents involving Semtex, and notes they killed
284 ( of which 270 were at Lockerbie, and 11 at the Deal barracks),
whereas 3288 incidents involving other explosives killed 107. He
was emphasising that Semtex is not unusual. In one " own goal "
in a car three terrorists were putting the finishing touches to a
300 ball bearing / 85gram Semtex claymore mine intended to
disrupt an anti-Khomani meeting, when it exploded. The driver's
surname was Fooladi, :-) - he was the only survivor, 10 years at
her Majesty's pleasure... He also notes the various names of
the manufacturer - initially the Semtin Glass Works, then the
Eastern Bohemian Chemical Works, then Synthesia.
Another paper also notes that ICAO have insisted that volatile
taggants be added to involatile plastic explosives at manufacture,
and EGDN ( ethylene glycol dinitrate ) is now added to Semtex H.
Several papers also note that various batches contain various
levels of impurities and compositions, but all consider Semtex H
to have a minimum of 21.5% RDX and a maximum of 64.5% PETN
with around 14% of rubber and oil. There are a couple that note
that Semtex A1 is predominantly PETN, but as the above analysis
indicates it still has both, although I suppose some people may
ignore the few % of RDX. I've no idea of the relative volumes, but
th4e above articles indicate that H was the common terrorist
material of concern
I will add bits of this to the FAQ, with the reference. I suspect
the earlier reference I cited may be more comprehensive ( and
it's the same author ), but it's not accessible to me.
Bruce Hamilton
From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: sci.chem,alt.engr.explosives
Subject: Re: SEMTEX - what is it?
Date: 21 Dec 1995 00:38:09 GMT
Organization: Consulting Chemist
In article <B.Hamilton.627.30D794F7@irl.cri.nz>, B.Hamilton@irl.cri.nz
(Bruce Hamilton) says:
>In article <4b537i$k9@geraldo.cc.utexas.edu>
> glhurst@onr.com (Gerald L. Hurst) writes:
>>In article <...>, yshan@bnr.ca (Yogi Shan) says:
>[ my earlier cite to C&EN, noting that Semtex had
> both RDX and PETN deleted ]
>>>I find it strange that PETN would be mixed with
>>>RDX.
>...
>>You are right, Yogi. PETN and RDX are so similar in their explosive
>>properties that it would be foolish to mix the two and thereby
>>double the risk of some chemical incompatibility unique to one or
>>the other.
>
>>By coincidence, it happens that I have prepared and tested plastic
>>explosives that have about the same composition as the material that
>>is now called "Semtex." The compositions are very similar to
>>C-4 in look, feel and performance.
>
>Well, as promised, I looked it up. Experience tends to make me
>very suspicious of Gerald's assertions :-)....
>
>From:- "Analysis of Semtex Explosives" J.R.Hobbs.
>Chapter 39. p.409-428 in " Advances in Analysis and
>Detection of Explosives" edited by Jehuda Yinon
>Kluwer Academic Publishers ISBN 0-7923-2138-3 (1993)
>
>Table 1. Summary of Semtex Analysis
>
>Name Semtex H Semtex A
>% PETN 49.8 94.3
>% RDX 50.2 5.7
>Dye Sudan I Sudan IV
>Antioxidant N-phenyl-2- N--phenyl-2-
> naphthalamine naphthalamine
>Plasticizer n-octyl phthalate n-octyl phthalate
> butyl citrate butyl citrate
>Binder styrene-butadiene styrene-butadiene
> rubber rubber
>
>Table 2. Gravimentric Analysis
>Sample size 1.0194 1.1061
>Weight oil 0.0811 0.0994
>% oil by weight 7.9 9.0
>weight rubber 0.0920 0.1036
>% rubber by weight 9.0 9.4
>weight explosives 0.7029 0.7029
>[ rest of table omitted ]
>
>Note that other chapters highlight the fact that Semtex H was the
>explosive used in mainland UK. There is an excellent, droll
>chapter " The Semtex H Story" by A.W.Feraday,OBE - head of
>Forensic Investigations, Forensic explosives Laboratory. He
>describes all 58 incidents involving Semtex, and notes they killed
>284 ( of which 270 were at Lockerbie, and 11 at the Deal barracks),
>whereas 3288 incidents involving other explosives killed 107. He
>was emphasising that Semtex is not unusual. In one " own goal "
>in a car three terrorists were putting the finishing touches to a
>300 ball bearing / 85gram Semtex claymore mine intended to
>disrupt an anti-Khomani meeting, when it exploded. The driver's
>surname was Fooladi, :-) - he was the only survivor, 10 years at
>her Majesty's pleasure... He also notes the various names of
>the manufacturer - initially the Semtin Glass Works, then the
>Eastern Bohemian Chemical Works, then Synthesia.
>
>Another paper also notes that ICAO have insisted that volatile
>taggants be added to involatile plastic explosives at manufacture,
>and EGDN ( ethylene glycol dinitrate ) is now added to Semtex H.
>Several papers also note that various batches contain various
>levels of impurities and compositions, but all consider Semtex H
>to have a minimum of 21.5% RDX and a maximum of 64.5% PETN
>with around 14% of rubber and oil. There are a couple that note
>that Semtex A1 is predominantly PETN, but as the above analysis
>indicates it still has both, although I suppose some people may
>ignore the few % of RDX. I've no idea of the relative volumes, but
>th4e above articles indicate that H was the common terrorist
>material of concern
>
>I will add bits of this to the FAQ, with the reference. I suspect
>the earlier reference I cited may be more comprehensive ( and
>it's the same author ), but it's not accessible to me.
>
> Bruce Hamilton
Bruce and I have indeed had our discussions in the past
regarding a minor difference of opinion about the suitability of
using the principle of Archimedes to measure the density of
very water-soluble solid materials. Bruce may like to tell you
which side of that argument he supported.
So, we have found some analyses of materials said to be
"Semtex-X" that contained anywhere from 21 to 64 percent PETN
with the balance RDX and inerts. You don't suppose these could
be the result of the extreme financial problems in the old
eastern block, especially in the period 1993?
The Russians and Poles, etc are very good at the science of
high explosives so they know that it is unwise to specify
the unnecessary use of two components in an explosive mix
where one will do. Not only does it increase the likelyhood
of chemical incompatibility, but it puts your manufacturers
in the position of having to carry double inventories, which
is a hell of a stupid thing to do when you are dealing with
national defense.
We have already discussed the fact that there is little
difference in the performance of plastique made from RDX
or PETN. I suspect that the Semtex being glommed onto by
terrorists is a kitchen sink material made up of whatever
proportions of HEX types they can find. If comrade Vladimir
gets Col Khadaffi's order for a few tons of plastique, and
Vlad finds he is out of PETN from the Chernobyl plant, does
he apologize and not fill the order because he doesn't have
the "minimum" 21 percent PETN? Or does he simply manufacture
"Semtex U," short for USA, a material remarkably like C-4?
As long as these guys can get their hands on either PETN or
RDX individually or in a mixed ordnance scrap pile, they will
continue to manufacture "Semtex" and people will continue
to ask "What is the composition of Semtex?" I would be
willing to bet that there is plastique "Semtex" out there
adulterated with TNT, HMX (They should be so lucky) and tetryl
as well and probably a good bit of it cut with inerts to the
cap-sensitivity limit..
According to your gravimetric analysis table II, the total
explosive contents of Semtex "A1" and "H" respectively
are 64 and 69%. The corresponding oil/rubber contents are
17 and 18% for totals of about 81 and 87%. Based on the ratios
in table 1, the RDX would be 5.7*.64 = 3.6 percent which is
far less than the material not accounted for.
Three or four percent sounds like an amount which can be
assigned to residue from not cleaning the mixer between batches.
There is not a great deal of difference in the explosive
performance of RDX and PETN, but there are valid military
reasons to prefer the former (sensitivity, stability). There
are are also good reasons to use PETN in commercial
applications - it is powerful and cheap. Now, the old Eastern
Block's ordnance was second to none in those areas where they
had the necessary skills, and they definitely knew at least as
much about explosives as we do.
Most explosives chemists are very used to the idea of
interchanging RDX and PETN in various commercial formulations
depending on the price of the materials. In this country we
use RDX for primers when the government deigns to sell off old
surplus material. If I had an order for 1000 1lb 50% cast
primers, but only 250 lbs each of RDX and PETN do you suppose
I would make up two batches of 500 lbs each or one batch of
1000 lbs. Regardless what went in, the customer would probably
think of it as "pentolite." For the quarry operator, no harm
done, but Uncle Sam wouldn't buy it.
A military formulator, whether here or in Poland would not
make a plastic explosive from PETN if he/she had access to ample
RDX unless the object was to save money, in which case he/she
would simply use PETN. The use of a PETN/RDX mixture would be
an expedient measure when supplies were short and the customer
was desperate or not too particular, as in the case of Middle
East terrorists. Adding 5% RDX to a PETN formulation would
produce undetectable performance changes, but it would make
good sense if you had some surplus RDX available, commercial
access to all the PETN your rubles can buy and willing buyers
other than your own fussy military.
Note that the analyses indicate an excessively high proportion
of inert materials, way beyond the less than 10% required to
impart adequate plasticity. Looks like somebody has their
thumb on the scale, doesn't it? Or do you suppose the Eastern
armies don't object to carrying around a little totally useless
baggage in combat? It is more likely that the high inert values
are a reflection of the fact that terrorists will buy anything
that goes "boom" most of the time.
I understand that they are giving away a free sample of "red
mercury' with each case of Semtex. Perhaps we can have a debate
about the precise composition of the former sometime.
For those of you who like pigeon holes and lables, we could make
a sliding scale for "Semtex" formulations using all the letters
of the alphabet to designate closely the percentages of RDX as a
function of total explosive content and number designators to
represent the percentage of inerts. On a ternary graph this
would produce a large area of compositions with a single dot on
the RDX/inert axis labled "Semtex C-4."
Should you ever need to order some Semtex for a demolition job,
be sure to nudge the salesman and tell him you want the good
stuff. Else what you get will be just about any composition up
to, but not including C-4 or Detasheet.
Bruce admonishes:
>Experience tends to make me very suspicious of Gerald's
>assertions :-)....
Bruce does a lot very good work in providing an excellent chemistry
FAQ and he knows more about gasoline than any three other chemists
I've met. If he says my assertions are suspicious, he is probably
right, especially if he knows as much about military explosives as
he does about hydrocarbon mixtures.
All I know is what I picked up walking by the door where the
smarter guys were discussing explosives. Bruce is much more
academically inclined than I am. The result may be that he
sees "Semtex" as a necessary specifier for a poorly defined
continuum of formulations with sub-classifications "A" and
"H" which are also indefinite compositions.
My relatively non-academic brain revolts at this concept and
insists that there really isn't any such thing as "Semtex"
except insofar as we choose to use the term for any plastique
which is analyzably not C-4 or C-3. Of course, there may be an
"original Semtex" which actually had a specific composition.
If there was, then what we need is the original official spec
sheet, not an analysis of something we found in a bomb at the
embassy.
I have this dream in which they find a brief case bomb
containing a plastic explosive which is not C-4. Analysis
shows it to be form of Semtex. I read the analysis and realize
that it is material I made 20 years before "Semtex" was
invented and that was left in some long-abandoned storage magazine
which has fallen into the wrong hands. I keep my mouth shut.
One of the doors I passed in the old days belonged to Israeli
security people. They invited me in, touched a pea-sized ball
of dynamite to my palm and then showed me how their detection
instruments went wild in the vicinity of my subsequently
cleaned hand. This was a truly impressive demonstration of their
ability to detect the EGDN used in nearly all dynamites.
It would not surprise me at all if they and others fearing
terrorist attacks wished EGDN into the formulations as an easy
way to make them detectable with existing equipment. If I were
selling such equipment, I might be tempted to lobby for rules
requiring the addition of EGDN to plastique, but I'd hate to
have to manufacture the material.
Is EGDN addition really a good Idea? I don't think so. EGDN is
chemically and physically unstable compared with any military
explosive and it is a vasco-dilator that can put you in
the hospital if you handle it too much as in molding a plastic
explosive. In this country we have gotten rid of all our
NG/EGDN explosives plants save one for good reasons. Who now
wants to actually manufacture and transport EGDN purely for
use as a taggant? Those who sell off the shelf dynamite
detectors, of course - now that terrorists are unlikely to use
dynamite.
Mind you, all I know is what I heard walking by the doors and
my perspective on matters such as explosives nomenclature and
acceptable formulations may be warped by too little time spent
in the library and too much spent in the hallways.
Jerry (Ico)
What do you get when you combine a gram of Semtex, a gram of
red mercury and a gram of polywater in a cold fusion apparatus?
A lot of hot air.
From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: alt.engr.explosives
Subject: Elusive Semtex
Date: 24 Dec 1995 21:56:57 GMT
Organization: Consulting Chemist
Next to Red Mercury and Cold Fusion, nothing seems so hard
to pin down as "Semtex," the mystical plastic explosive
from Eastern Europe with the elusive composition. If you
read enough opinions you will learn that it is made of
anything from petrolatum and sodium chlorate to an
indefinite plasticized PETN and/or PETN/RDX mixture. The
latter type compositions, especially those with both RDX
and PETN are backed by some reputable analyses, but the
question remains as to why there would be so much apparent
variability in composition. Flexible compositions are not
a hallmark of military materials, but they are the stuff of
profit-driven commerce. The following is a very speculative
theory which attempts to explain the apparent existence
numerous types of "Semtex."
RDX is somewhat less sensitive than PETN. This is an
advantage to the military because it means the former
can better resist impact initiation in battle. Properly
formulated plastic explosives such as C-4 contain as high
a percentage of RDX as can be crammed in without losing
the limited coherency of the material, which is a stiff,
claylike mass.
Despite the high explosives content of C-4, it is difficult
to initiate the material with a #6 blasting cap and failures
also sometimes occur with commercial #8 caps when they are
not properly positioned in the charge.
Now look at the closest commercial equivalent of C-4, Detasheet,
manufactured by du Pont. Detasheet is based on plasticized PETN
and is designed to be a cuttable sheet material with a rubbery
consistency which holds its dimensions under reasonable abuse.
The physical stability of Detasheet makes it well adapted for
such applications as metal cladding and plane wave generators.
Because of the higher sensitivity of the PETN, detasheet
tolerates relatively high concentrations of rubberizing
ingredients.
If we look at the availability of explosives world-wide from
the perspective of an entrepeuner, we see that he can always
purchase PETN on the open market. RDX, on the other hand, is
only available at a reasonable cost on those relatively rare
occasions when some government is selling off surplus stocks.
So, Mr. Entrepeneur formulates his plastique in the cheapest
way possible using PETN and all the passive materials he can
put in without losing cap sensitivity. He is not at all
concerned about the strength of his product as long as it
shoots.
Time passes and our businessman gets his hands on some price
competitive RDX. His first new batch of "Semtex" is a dud, it
won't shoot. He could raise the concentration of RDX up to 91
percent to make "Semtex C-4", but that would raise his costs
significantly. Then he finds a happy compromise. He blends in
enough PETN to allow the retention of cap-sensitivity at
higher inert dilutions.
Batches containing about 50/50 PETN/RDX can tolerate a hefty
30 percent or so of inerts while material with 95 percent
PETN handle a whopping 35 percent, and so on.
Without a rather sophisticated laboratory, your average
terrorist is unlikely to be able to tell 50/50 from 95/10, but
he can estimate the total explosive content by noting a couple
of solubilities (acetone and ligroin), so our vendor puts
labels on the material: "H" for "hardly detonable" and "A" for
"Awfully adulterated." This act of honesty helps assure the
manufacturer that he won't receive any "returns" from his
customers.
The above is nothing more than another outrageous theory from
a notoriously unreliable source, but it could explain why
intercepted "Semtex H" seems to contain "not less than 21% PETN
and not more than 64.5 percent RDX." These would be screwy
compositions from a military standpoint, but quite logical
in terms of a commercial bottom line and a not overly discerning
customer.
Jerry (Ico)
Subject: Re: Semtex
From: glhurst@onr.com (Gerald L. Hurst)
Date: Dec 03 1996
Newsgroups: alt.engr.explosives
In article <57vreb$oic@crl3.crl.com>, gherbert@crl.com (George Herbert) says:
><mikedean@austin.ibm.com> wrote:
>>RDX was first made in 1899. Don't know when they figured out how to use it
>>like C4. Probably sometime between WWI and WWII. C4 was used in WWII.
>
>According to my references, "Composition C" was in use in WWII but C-4
>postdates that conflict. Comp B (still in use) and Comp C (close to C-4,
>but not quite the same) were invented right before WWII.
Comp C-3 was the common WWII explosive. In addition to RDX it
contained TNT, tetryl, DNT/MNT oils and a dash of NC. One used
to find the material in the form of canvas satchel charges. As
the material aged, it would become a bit brittle, yellow and
crusty but massaging it brought it back to its pliable consistency
and it shot just fine after 30 years of hot and cold magazine
storage. The DNT oil gave the composition a rather pleasant
odor -- kind of reminiscent of gun cleaning solvent (Hoppe's #9).
The performance of C-3 was quite good but the material was
somewhat more toxic than was desirable and it's low temperature
plasticity was said to leave something to be desired. I never
noticed this drawback but also never used the material for any
really difficult work much below below freezing.
Jerry (Ico)
From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: alt.engr.explosives
Subject: Re: What is C4 made of?
Date: 11 Mar 1997 22:22:04 GMT
In article
<Pine.A41.3.94.970311142525.15586B-100000@acs2.acs.ucalgary.ca>, Daniel
John Krut <djkrut@acs.ucalgary.ca> says:
>I am a chemistry student at the U of C and am wondering how C4 is produced
C-4 is a simple mechanical mixture of powdered RDX (cyclonite) and
a plasticizing mixture in the ratio 91:9. The specific plasticizer
mix is comprised of:
Polyisobutylene 2.1
Motor oil 1.6
Di(2-ethylhexyl) sebacate 5.3
There is no particular magic in the specific plasticizer mix other
than that it has good stability and low-temperature plasticity. It
may be viewed as an inert diluent as far as explosive properties go.
Jerry (Ico)
From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: alt.engr.explosives
Subject: Re: plastic explosives
Date: 8 Jan 1996 19:27:57 GMT
In article <4cr9r2$hap@norm.uoknor.edu>, major@rodent.ecn.uoknor.edu (Dan
Major) says:
>Could someone please post the aproximate densities of common plastic
>explosives (semtex, C-4, etc.). Or even the densities of some *uncommon*
>ones if you know of any.
The loading densities of C-3 and C-4 are 1.58 and 1.60
g/cc respectively. Note that these are "loading densities";
crystal densities could be as much as about 0.1 greater.
There are apparently a variety of "Semtex" materials. Their
densities will be somewhat lower than C-4 because they seem
to frequently use a lot of PETN, which has a lower density
than RDX and much more inert plasticizer/filler which have
much lower density than either explosive. I would expect
some samples to run as low as 1.4 g/cc or lower.
Jerry (Ico)
From: arno@sol.utu.fi (Arno Hahma)
Newsgroups: alt.engr.explosives
Subject: Re: PETN in Plastic explosives?
Date: 20 Feb 1997 16:33:45 +0200
In article <330A83CB.755D@umr.edu>, Brandon Weeks <brandonb@umr.edu> wrote:
>> Does anyone know of any produced plastic explosives that contain PETN
>> as the main explosive?
>Detasheet
In addition to that, some versions of Semtex are based on
PETN. Also, PENO and NSP 862 are PETN based plastic
explosives.
ArNO
2
From: "Gerald L. Hurst" <GHURST@austin.rr.com>
Newsgroups: alt.engr.explosives
Subject: Re: Trivia
Date: Fri, 08 Oct 1999 18:01:02 GMT
Well, maybe not really :) You have to remember that materials
we call "plastics" were first invented in this century. We have changed
the meaning of word to cover all synthetic resins, including celluloid,
(nitrocellulose mixture), which is not plastic at all but rather rigid.
"Plastic" in the original sense meant deformable without resiliency.
In this sense, most nitroglycerin explosives have always qualified.
The materials loosely referred to as "dynamite" were nearly all
readily tampable and therefor "plastic" in the first sense.
The composition cited in the subject post is not significantly different
from the common "dynamites" made from NG and various cellulosic
substances such as wood pulp, bagasse, etc. until just a few years
ago.
What is different about the cited mixture is the incredibly stupid addition
of excess acid to the mix. The dummy who thought this up was
apparently unaware that great efforts are required to remove acid from
NG mixes or at least neutralize excess acid to prevent spontaneous
decomposition of the NG.
A better candidate for "the first plastic explosive" would be the original
blasting gelatins manufactured by Nobel himself. These were mixtures of
nitroglycerine and nitrocellulose, vaguely akin to the cotton formulation
being discussed insofar as that cotton was nitrated.
I have used the quotes around "dynamite" to indicate an extrapolation
to products other than that obtained by mixing NG with
diatomaceous earth (Kieselguhr).
Jerry (Ico)
donald haarmann <donald-haarmann@worldnet.att.net> wrote in message
news:7tk8js$v5$1@bgtnsc02.worldnet.att.net...
> The first plastic explosive was that of Max Jeschek and Josef Jaresch of
> Wein. DP 44 041 "Process for the Manufacture of Acid Plastic Explosive"
> 29 March 1887
>
> "By adding 20% to 40% of cellulose (cotton, straw, hemp. flax. etc.) to
> liquid explosives consisting of nitro derivatives and sufficient
> concentrated nitric acid for complete combustion, plastic explosives are
> produced. Extra nitric acid is added in sufficient quantity to nitrate
> the cellulose and provide oxygen for its combustion."
>
> Must of been some exciting stuff in storage!!
>
> A practical plastic explosive based on TNT was patented 1905.
>
>
> --
> donald j haarmann - eminence grise
From: "Gerald L. Hurst" <GHURST@austin.rr.com>
Newsgroups: alt.engr.explosives
Subject: Re: Trivia
Date: Sat, 09 Oct 1999 00:33:17 GMT
donald haarmann <donald-haarmann@worldnet.att.net> wrote in message
news:7tlg1v$59i$1@bgtnsc02.worldnet.att.net...
> -----------
> Plastic is taken to mean - capable of being molded or receiving form.
> I doubt that gelatins count.
[snip]
The Atlas Powder Company traced its history back to the Giant Powder
Company, Nobel's American dynamite manufacturer founded in 1867. Nobel
invented gelatin in 1875. In the official Atlas version of the story,
they describe the invention as follows:
In 1875, Nobel cut his finger and applied the collodion [invented by med
student Maynard]. He then decided to try its effects on NG, which resulted
in a very PLASTIC and cohesive gelatin. [My caps and brackets]
Jerry (Ico)
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